1. Field of the Invention
The present invention relates to an automatic method of passively determining sniper positions which are randomly located in the surroundings by utilizing a simple stationary or mobile listening station consisting of an intelligent listening system which comprises two or more microphones together with a compass for supporting the solution.
Such a surveillance method of shooting activity is of the utmost importance during unsafe conditions when snipers are especially active, as it may be during UN operations, and the importance of identifying the position of such activity is vital. The method is meant for stationary as well as for mobile activities. A stationary solution can be useful in areas such as airports, official buildings, military facilities, private buildings, VIPs in governmental administration, and other unsafe areas. The method can be utilized for mobile activities such as being hand held in the battle field, and being mounted on a car when driving in unsafe areas.
Equipment that is utilizing the present invention can be located at areas with shooting activities, and can be mounted on a car that is moved into the area. Remote monitoring by radio satisfies the safe monitoring of the situation when gunfire is registered.
2. Description of Prior Art
Various methods for the detection and positioning of sound sources are conventionally known and these are disclosed, for example, in GB-3,336,245, GB-2,062,864, GB-2,099,995, U.S. Pat. No. 3,838,593 and U.S. Pat. No. 3,626,750, GB-1,349,120, NO-1,39,240, GB-1,174,048, GB-342,800, GB-1,452,788, GB-2,167,556, U.S. Pat. No. 4,372,151, U.S. Pat. No. 4,543,817, WP 82/00718, NO 169678, GB-A,2,181,238, U.S. Pat. No. 4,333,170, EP-A,64,477, GB-A,2,191,580, U.S. Pat. No. 5,070,484 and U.S. Pat. No. 5,099,455.
A majority of these conventional methods deal with leakage in pipes, and thus they assume that the sound moves through solid material. As a result, these conventional methods distinctly deviate from the present invention. Most methods are oriented towards leakage problems in situations where the positioning can be achieved along one line (one dimensional). The EP-A,64,477, GB-A,2,181,238 and NO 169678 references, on the other hand, are utilized to detect and determine the direction to and the position of acoustic sound through air, they all utilize more than one microphone cluster for such positioning, and they have several microphones in each cluster for that purpose. The EP-A,64,477 and GB-A,2,181,238 references are related to weapons and gunfire. Most of these methods use several intercepting directional vectors with a base in several microphone clusters in order to determine the position of sound origin. The GB-A,2,191,580 reference uses an array of distributed microphones to determine the position of weapons by sound.